Heat exchangers for transferring thermal energy between fluids such as gases and/or liquids commonly use finned metal structures formed from thin metal sheet material in order to more effectively transfer heat to or from the fluids. Such finned structures provide advantages by increasing the amount of surface area available to the fluid for convective heat transfer to occur, while minimizing restrictions in free flow area that inevitably result in undesirable flow resistance.
In certain circumstances, it may be necessary or desirable for other structures of the heat exchanger to extend through what would otherwise be available finned flow area for a fluid. As one example known from the prior art, U.S. Pat. No. 9,038,610 to Meshenky et al. shows a heat exchanger for cooling a flow of compressed charge air wherein ports for a coolant flow and a structural retention member are centrally located along the air flow path and extend through the height of the heat exchanger. In a heat exchanger disclosed therein, the ports and fastener are accommodated by providing two air fins at each air channel level, with a central space between the two air fins reserved for the coolant ports and fastener. Such an arrangement leads to an increase in parts, which can be undesirable.
For liquid flows, the aforementioned problem can often be addressed by forming apertures into the fin itself, as shown and described in U.S. Pat. No. 7,255,159 to Sagasser et al. The finned structures used for liquid flows and other similarly high-density fluids are typically of the stamped turbulator variety depicted in that patent, and are thereby relatively amenable to having apertures stamped into the finned structure as shown therein.
However, forming such features into the fin structures used for lower density gas flows, such as for example air, has proven to be much more difficult. Fin structures used for such flows are typically formed from thinner material, and are typically substantially taller in height and have substantially tighter fin spacing. Attempts to use the conventional stamping processes used for liquid turbulators on such air fins have been unsuccessful, resulting in severe deformation of the fin convolutions and causing impaired performance and assembly difficulties. Thus, there is still room for improvement.